1. Field
Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to managing group identifiers (IDs) in multiuser multiple-input multiple-output (MU-MIMO) schemes to ensure that the group ID maps to the same assigned spatial stream position for a particular station (STA), for either Direct Link Service (DLS) or downlink (DL) MU-MIMO transmissions.
2. Background
In order to address the issue of increasing bandwidth requirements demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs. Multiple Input Multiple Output (MIMO) technology represents one such approach that has recently emerged as a popular technique for next generation communication systems. MIMO technology has been adopted in several emerging wireless communications standards such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. IEEE 802.11 denotes a set of Wireless Local Area Network (WLAN) air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters).
A MIMO wireless system employs a number (NT) of transmit antennas and a number (NR) of receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas may be decomposed into a number (NS) of independent channels, which are also referred to as spatial channels or spatial streams, where NS≦min{NT, NR}. Each of the NS independent channels corresponds to a dimension. The MIMO system can provide improved performance (e.g., higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.
In wireless networks with a single Access Point (AP) and multiple user stations (STAs), concurrent transmissions may occur on multiple channels toward different stations, both in the uplink and downlink direction. Many challenges are present in such systems.